oaiharvest: update model
oaiharvest: fix CLI program
BibConvert: Exceptions management fixes

* Removes question mark at the begining of xml which wasn't accepted
  by the xml parser !

* Add a new management of exceptions by raising exceptions instead of
  returning None.
Celery: Default changed from Msgpack to cpickle

* Change the way to serialize message to communicate with celery
  to serialize complex object we need to use cpickle instead of
  Msgpack
Plotextractor: XML direct output option

* Add the possibility to get a direct XML output
  this aims to avoid useless acces to the disk and
  so not use files. It should speed up some process
OAIHarvest: Integrate new workflows

* Refactor oai_harvest_daemon to use new workflows module for
  post process.

* Several PEP8 fixes.

Bibworkflow: MarcXML processing workflow

* Sub workflow exception improvement which allow to centralize all the exceptions of
  children workflow and to get the full stacktrace of each

* Convert_record_to_bibfield task for workflow which convert any marcxml file to a
  dictionnary thanks to bibfield, the goal is to avoid the old file system based
  inter function communication protocol

* Post_process after celery reception of an WorkflowObject to reattach to the new
  DB instance all the DB object which couled be not referenced

* Add security of type cohesion into the WorkflowObject Transporter, it is a hot fix
  in wait of the database modification which allow to tranform potential string
  representation of dictionnary into dictionnary.

* New workflow tasks, all compatibles with bibifield dictionnary representation
  fulltext_download with bibfield support, plot_extract with bibfield support,
  ref_extraction witht bibfield support, author_list witht bibfield support

OAIHarvest: Various import fixes and PEP8
BibUpload: PEP8 fixes
BibTask: Option to return all task options

* In case of None key in retrieving parameters we
  get the full dictionnary.
legacy: migrate OAIHarvest CLI

* Migrates the CLI of OAIHarvest to the new method.

* Fixes bad import in upgrade script.
Workflows: Fix celery workflows worker

* Fix a problem with with_app_context, no celery worker
  is working fine!
Correction of imports and merge comments
Merge pull request #118 from PXke/commit-try-A

Commit try a